1. Field of the Invention
The present invention relates to an electric connection box.
2. Description of Related Art
An electric connection box shown in JP-A-H9-214158 is conventionally provided. The electric connection box is installed on a vehicle, and used for ON/OFF control of vehicle electrical components. In the electric connection box, a bus-bar board and a circuit board are vertically disposed in a casing, and arranged parallel to each other. A plurality of bus bars constituting a power circuit are arranged on the bus-bar board, while electronic components are mounted on the circuit board.
Further, relay attachment portions for connecting relays are provided on the wall of the casing. The number of relays to be connected to the electric connection box is increasing due to recent increase of electrical components to be installed on a vehicle. However, limited space for the electric connection box can be provided in the vehicle, and therefore the relays should be mounted in the electric connection box in higher density.
In view of this, there has been proposed that relays are mounted on the bus-bar board. Thereby relays can be mounted in higher density, compared to the case in which relays are attached to relay attachment portions on the casing. However, in the case that relays are mounted on the bus-bar board as described above, there arises a problem that the electronic components mounted on the circuit board may be damaged due to heat generated by the relays.
Thus, there is a need in the art for an electric connection box having an improved heat-releasing property.